An introduction to RALF

D 19 February 2015

RAdio Logicielle pour la Formation (RALF): an educational software defined radio platform at the University of Toulouse.

Project summary

The RALF project has been carried out by the University of Toulouse/ISAE-Supaero (since 2014) in order to promote Software Defined Radio (SDR) techniques in several engineering trainings. One can define a SDR transceiver as a generic hardware device (typically wideband with high sampling rate) where all application-related signal processing is performed in the digital domain thanks to a host computer or an embedded controller. It results in a highly flexible architecture, generally made of high-level software building blocks allowing to move from an application/standard to another within a tenth of second.

possible connection with research topics (from a simulator to a demonstrator);

source code oriented project management, more and more used in the industry (e.g. agile, eXtreme programming).

For all those reasons, we believe that SDR can be a valuable professionalizing approach to bridge the gap between theory and practice in the field of telecommunications and signal processing.

Examples of applications

The wide frequency range covered by our transceivers enables a large set of potential applications:

aeronautic (ACARS, VDL mode 2, ADS-B, HFDL...);

satellite (NOAAAPT, DVB-S...);

cellular (GSM, UMTS, LTE, POCSAG...);

home automation (CCIR tones...);

amateur radio (SSB, APRS, PSK31...);

audio and video broadcast (FM, DVB-T, DRM...);

direction finding (AOA, TOA...);

An USRP B200 station

A FM receiver flowgraph with GNURadio Companion

Waterfall plot in the GSM band

A QPSK modulation observed with GNURadio

A typical RALF workbench

An USRP N210 transceiver

Organization

The project has been funded by the University of Toulouse (23 k€) and ISAE-Supaero (13 k€). It includes several members: ENAC, ENSEEIHT, INSA, UPS. RALF also benefits from the experience and hardware resources from several partners such as GIPSA-lab, National Instruments and TELECOM Bretagne. More information is given on the team page.